This application relates to optical frequency reference and applications use such a reference.
Atomic or molecular transitions in various atomic or molecular media may be used to provide precision frequency references in a variety of applications. For example, many precision laser applications require frequency stability on both short and long time scales, and sometimes even absolute frequency calibration. Atomic and molecular gases are commonly used to produce frequency references for stabilizing lasers and locking laser frequencies. Frequency locking in a laser can be achieved by reference to an atomic absorption line in an atomic or molecular gas. Bulky glass absorption cells and free space optics are typically used in such frequency locking systems.